Psychological Defense Mechanisms as Interactions between Hierarchical and Hemispheric Functions

Abstract

In Chapter 13, we described the biological defense against the danger of the organism being overwhelmed by an excessive emotional reaction to threat as a brain stem mechanism that reduced the arousal level of emotionally threatening stimuli by inhibiting the cognitive component. That response was illustrated in animals by the Olds et al. paradigm in which negatively charged stimuli provoked no greater cognitive response than did neutral stimuli in thalamic nuclei (Fig. 13-2). A related effect in humans was demonstrated in the Begleiter et al. study (Fig. 13-3) where negatively charged stimuli, despite being associated with a higher level of arousal than positively charged stimuli, consistently produced evoked cortical responses of lower amplitude. The putative explanation for this latter finding was given as a presumed inhibition of negatively charged stimuli during upstream processing in the brain stem, with subsequent enhancement during processing to consciousness. The case for the differences between unconscious and conscious processing of negatively charged stimuli—inhibition for unconscious stimuli and excitation for conscious stimuli—was supported by the studies of Kostandov and Arzumov (1980) and by Shevrin et al. (1967, 1974, 1980).